Hypoxemia Due to Aspiration of Water in Dogs
Near-drowning is determined by an event that involves prolonged submersion in water, followed by survival for at least 24 hours afterward. Following submersion, typical symptoms include elevated carbon dioxide levels in the bloodstream, stimulated respiration, and subsequent aspiration of water into the lungs. In rare cases, hyperventilation prior to submersion, or laryngospasm (spasmodic closing of the larynx) may prevent aspiration of water, an involuntary reaction that can lead to a condition called dry drowning.
There are four phases in a typical drowning: breath-holding and swimming motion; water aspiration, choking, and struggling for air; vomiting; and cessation of movement followed by death. The mammalian diving reflex may occur, leading to a slowed heart rate, a halt in breathing, and blood circulation limited only to the essential organs of the body. Large volumes of water are not typically aspirated at this stage.
Fresh water aspiration leads to a collapse of respiratory cells with possible infectious pneumonia. Hypertonic seawater aspiration leads to a diffusion of water entering the lungs and into the alveoli (the air cells of the lungs). Since the dog cannot obtain enough oxygen, oxygen levels in the blood drop and the blood becomes acidotic (abnormal increase in acidity).
Submersion time, temperature of the water, and the type of water the dog is submerged in (whether the water is fresh, salt, or chemical) will significantly affect the development of organ damage.
Symptoms and Types
- Bluish skin and gums
- Coughing with clear to frothy red sputum (spit-up)
- Cessation of breathing
- Difficulty breathing
- Crackling sound from the chest
- Semi-conscious and dazed to comatose
- Increased or decreased heart rate
- The heart may cease to beat
- Owner negligence
- Inadequate safety precautions
- Young, inexperienced dog (less than four months of age)
- Dog was in or near water at the time of a seizure
- Following head trauma
- Rapid drop in blood sugar, abnormal heart beat rhythm, or fainting episode while in body of water place dogs at higher risk of drowning
Your veterinarian will perform a complete physical exam on your dog. Standard laboratory tests will include a blood chemical profile, a complete blood count, a urinalysis and an electrolyte panel.
Chest X-rays may show aspiration pneumonia or fluid in the lungs one to two days after the near-drowning. Foreign body inhalation may produce segmental lung collapse. Pulmonary injury progressing to acute respiratory distress syndrome (ARDS) is possible.
An endotracheal or transtracheal wash, followed by a cytologic evaluation and culture with sensitivities is indicated. Electrocardiographic monitoring to examine the electrical currents in the heart muscles may be performed to assess heart damage. Your veterinarian will also want to determine the auditory evoked response (BAER) for hearing loss assessment. Cervical X-rays, computed tomography (CT), or magnetic resonance imaging (MRI) of the brain and brain stem may be helpful in select cases.